如图所示为两电阻R1和R2的伏安特性曲线。将电阻R1和R2接入如右图所示电路中，闭合开关s后，当滑动变阻器触片P向下移动时，则（ ）
A．电流表示数增大
B．电压表示数增大
C．电源的总功率增大
D．电阻R1上消耗的电功率大于电阻R2上消耗的电功率
答案：D
题目分析：若滑动变阻器向下滑动，滑动变阻器接入电路的电阻增加
整个回路的总电阻增加，根据闭合电路欧姆定律，整个回路的总电流减小，因此电流表示数减小，A错误；电阻
与
分得的电压减小，电压表示数减小，B错误；电源的总功率
减小，C错误；根据伏安特性曲线可知，
，而两个电阻并联，电压相同，因此
，根据
可知，电阻R1上消耗的电功率大于电阻R2上消耗的电功率
D正确。
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| Mr. Glen is a millionaire. Five years ago, after returning from abroad to his motherland, he 1 his small company. Speaking of success, Glen often tells us a story about his extra expensive “school” fee. He always 2 his success to it. At that time, Glen, who already got a PhD degree, 3 to return to the homeland, starting a company. Before leaving, he bought a Rolex watch with the 4 made through years of work after school and the scholarships. At the airport he had to accept the 5 customs check. The watch on his wrist was also demanded to be taken down for 6 . Glen knew that carrying the specific goods out had to pay the tax, and he worried about paying 7 for his watch. So when he was checked, he told a lie that his watch was a 8 fake（假货）. When he was 9 of his " smarts" , immediately, in the presence of Glen, the officers hit the watch, 10 cost nearly 100,000, into pieces 11 hearing Glen's words. Glen was 12 . Before he understood why, he was taken to the office to be examined 13 . For many times of entry-exit 14 he knew that only those people in the "blacklist" would “enjoy” this special treatment. The officers looked over everything carefully in the box, and 15 him no matter what time of entry and exit he must accept the check and if 16 reusing and carrying fake and shoddy（劣质的）goods, he would be 17 according to law! Suddenly, his face turned red, and he had nothing in mind after boarding the plane for long. After returning to the homeland, he often told the story to his family, and his employees, too. He said that this made a deep 18 on him, because the additional high " school" fee that he had ever paid made him realize the value of 19 , which he would remember as the 20 of his success forever. | ||||
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